1. Technical Field
The present invention generally relates to insulating glazing units and, more particularly, to a method for applying a sealant to a spacer body and forming an insulating glazing unit with the sealant-laden spacer body. Specifically, the present invention relates to a method for applying a sealant to a spacer body and then forming a glazing unit without disturbing the sealant disposed on the spacer body to minimize sealant failures.
2. Background Information
Insulating glazing units generally include first and second glass sheets that are spaced apart and held by a perimeter spacer. A wide variety of spacer configurations are known in the art. A common feature to the spacers is that they physically separate the first and second glass sheets while providing a hermetic seal at the perimeter of the glass sheets so that an insulating chamber is defined between the glass sheets and inwardly of the spacer. The hermetic seal is formed by a primary sealant that is disposed across at least the interfaces between the spacer body and the glass. The hermetic seal may be formed entirely by the primary sealant or by the combination of the primary sealant and an element (such as a metal foil) of the spacer body.
The primary sealant that hermetically seals an insulating glazing unit is applied to spacer bodies in different locations, manners, and times in prior art insulating glazing unit fabrication systems. In one fabrication system, the primary sealant is applied into a channel formed between a pair of glass sheets and outwardly of the spacer. This type of system is shown, for example, in U.S. Pat. No. 3,759,771. A drawback with this type of system is that the application of the primary sealant is designed for both the spacer and the glass. The application method is thus not optimized for either component individually. In another fabrication system, the primary sealant is applied to a spacer body before the spacer body is placed into a storage and shipping container that is used to delivery the spacer body to the location wherein the insulating glazing unit is manufactured. This type of spacer system is shown, for example, in U.S. Pat. No. 4,431,691. In these types of systems, the sealant-laden spacer bodies are removed from the storage containers and then applied to one sheet of glass to form a perimeter frame. The sealant-laden spacers may also be removed from their storage containers, formed into a frame, and then applied to the glass. The second sheet of glass is applied to form an outer channel. The components are then passed through a heated roller press to wet out the primary sealant against the glass to form the primary seal. In these embodiments, the primary sealant applied to the spacer body can be damaged during storage, shipping, and handling before it is applied to the glass. Damaged sealant can create a leak that requires the window manufacturer to replace the window under its warranty policy. Another drawback with these systems is that the temperature of the sealant is difficult to control when the sealant initially engages the glass. One solution to these problems is to apply heat and pressure (such as by passing the unit through a heated roller press) to ensure good adhesion between the sealant and glass. These prior art methods have drawbacks and the art desires a solution that overcomes these drawbacks.